Economists usually analyze economic development at the national level, but the literature on creative destruction and misallocation suggests the importance of understanding what is happening at much smaller units. This paper does a development case study at an extreme micro level (one city block in New York City), but over a long period of time (four centuries). We find that (i) development involves many changes in production as comparative advantage evolves and (ii) most of these changes were unexpected (“surprises”). The block’s history illustrates how difficult it is for overly prescriptive planners to anticipate changes in comparative advantage and how such planning could instead stifle creative destruction.